Fixed a heap-UAF in RelocateARIAOwnedIfNeeded (CVE-2017-7809) DiD (accessibility is disabled)

DiD This means that the fix is "Defense-in-Depth": It is a fix that does not apply to a (potentially) actively exploitable vulnerability in Pale Moon, but prevents future vulnerabilities caused by the same code when surrounding code changes, exposing the problem.

Improving Mozilla code: You know you're on the right track with code changes when you spend the majority of your time deleting code.

"If you want to build a better world for yourself, you have to be willing to build one for everybody." -- Coyote Osborne